Yoghurt is a well-known fermented product popular in India and all over the world. The objective of the present study was carried out to incorporate encapsulated resveratrol powder into yoghurt and check the quality characteristics of it. The different proportions of encapsulated resveratrol powder with whey protein isolate as wall material was added to yoghurt. Based upon the sensory scores 1% level was finalized for further study.
Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume Number 08 (2018) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2018.708.331 Quality Characteristics of Functional Yoghurt with Fortification of Encapsulated Resveratrol Powder Harshita Sonarthi, S Sivakumar*, Rekha Chawla, N Veena, S.K Mishra, Lovepreet Singh and P.K Singh College of Dairy Science and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India *Corresponding author ABSTRACT Keywords Yoghurt, Encapsulated resveratrol powder Article Info Accepted: 17 July 2018 Available Online: 10 August 2018 Yoghurt is a well-known fermented product popular in India and all over the world The objective of the present study was carried out to incorporate encapsulated resveratrol powder into yoghurt and check the quality characteristics of it The different proportions of encapsulated resveratrol powder with whey protein isolate as wall material was added to yoghurt Based upon the sensory scores 1% level was finalized for further study The optimized yoghurt was compared with control for different proximate composition, texture, colour parameters, antioxidant activity, resveratrol content and microbiological parameters Sensory results shows non-significant difference (p≤0.05) between control and optimized product (WPI 1%) in all attributes WPI based wall material used for encapsulation of resveratrol powder could be successfully incorporated in yoghurt which could serve as a potential delivery system of resveratrol for enhancing functionality of the yoghurt Introduction ―Yoghurt is a popular fermented dairy product produced by the cultures‖ consisting of Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp Bulgaricus As per official website of National Dairy Development Board, India‘s milk production was increased from 55.6 million tonnes (1991-92) to 165.4 million tonnes (2016-17) (NDDB 2018) In India, 10% of total milk produced is converted into fermented milk products like yoghurt, dahi, lassi etc This sector is growing at more than 20 % (Singh, 2011) Yoghurt is famous due to the entry of a number of international and national organized dairy players in the market and gradually replaces the other dairy products due to its varieties and health benefits The period between 2011 and 2015, the yoghurt market in India grew at a compound annual growth rate (CAGR) of 28.9% and this market is projected to touch US$1 Billion by the end of the year 2021 Resveratrol (trans-resveratrol; trans-3,5,4trihydroxystilbene) is a polyphenol from the stilbenes family, found at relatively high 3102 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 levels in grape skins and also found in blueberries, raspberries, mulberries, peanuts and variety of other plant sources Resveratrol having potential beneficial effects on human health, including cardio and neuro-protective, antioxidant, protects from infection and ischemia antiviral, prevents ageing, antiinflammatory, anti-carcinogenic, and antiobesity effects (Alves 2012) The major drawback for incorporating resveratrol into functional foods are related to degradation when exposed to oxygen and or light, low water solubility, low bioavailability (Hung et al., 2006) In food industry, there is need for the edible delivery systems to encapsulate, protect and release resveratrol when developing functional food Encapsulation is one of the most promising technologies having the feasibility to entrap bioactive compounds like resveratrol The encapsulation further enhances the bioavailability, improve controlled release and enable precision targeting of the bioactive compounds in a greater extent (Mozafari et al., 2006) Keeping in view of this background, the present study was focused on to study the effect of encapsulated resveratrol powder on quality characteristics of yoghurt Materials and Methods Ingredients Fresh, clean, good quality mixed raw milk was obtained from Institute Experimental Dairy Plant This milk was standardized by using skim milk Skim milk was obtained by separating mixed milk in cream separator Yoghurt starter cultures NCDC 144 (L bulgaricus and S thermophilus) were procured from National Collection of Dairy Cultures, ICAR-NDRI, Karnal Materials required for encapsulation like milk protein based wall materials like Whey protein isolate, Resveratrol, Soylecithin, Olive oil, Maltodextrin, etc were purchased from the reputed firms for preparation of encapsulated resveratrol powder The packaging material polystyrene cups were procured from Institute Experimental Dairy Plant Preparation of yoghurt Milk was standardized to 3% fat and 10% SNF with whole milk and skim milk by Pearson Square method The standardized milk was heated to 85˚C for 15 The encapsulated resveratrol powder was incorporated at 70˚C The milk was cooled to 42˚C, after that inoculation was done with S thermophilus and L bulgaricus @3% at 42˚C Then it was transferred to incubation room for incubation for 4-5 hours, once the desired acidity was reached it was transferred to cold storage at 5˚C Sensory analysis The faculties from College of Dairy Science and Technology, GADVASU, Ludhiana participated in this study Prior to sensory evaluation, sensory panel was briefed about the desirable characteristics of the product Nine-point hedonic scale was employed to carry out the evaluation of samples for sensory attributes such as colour and appearance, texture, flavour and overall acceptability (Amerine et al., 1965) The nine-point hedonic scale includes various scales of grading i.e liked extremely (9), liked very much (8), liked moderately (7), liked slightly (6), neither liked nor disliked (5), disliked slightly (4), disliked moderately (3), disliked very much (2), disliked extremely (1) (Lawless and Heymann 1998) Analytical procedures The brief description of different methods used to examine physicochemical properties of functional yoghurt is given below 3103 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 was determined by DPPH (2, diphenyl-1picryl hydrazyl) method Physicochemical analysis Fat content, Protein content, ash content, titratable acidity of the product was done as per the method given by AOAC (2006) Moisture content was done by moisture analyzer Syneresis of yoghurt samples were done by using the method as described by Hassan et al., (2015) with slight modifications Texture profile analysis Various textural properties such as firmness, consistency, cohesiveness and index of viscosity were measured using Texture Analyser TA-XT Plus (M/s Stable Micro Systems, Surrey, UK) equipped with kg load cell A back extrusion test using 40mm cylinder probe was used for texture profile analysis of the yoghurt samples The product was subjected to compressive force by probe up to the distance of 30 mm For each evaluation, (3×3×2.5) cm3 size sample was used during texture analysis Numerical values of textural values were measured using the exponent software (version 6.1.1.0) The conditions set in the Texture Analyser for measuring textural properties were as follows: Pre-Test Speed, mm/s; Post-Test Speed, mm/s; Test speed, mm/s; Trigger force, 10.0 g; Time: 5.0 s Instrumental colour measurement Surface colour of yoghurt samples were measured using Colour Flex Colorimeter (Hunterlab, Reston, Virginia) supplied along with the universal software Easy Match QC (version 4.62) and the results were expressed in terms of CIE-LAB system (Hunter 1975) Antioxidant activity of yoghurt Radical scavenging activity of the yoghurt incorporated with encapsulated resveratrol Resveratrol content in fortified yoghurt with encapsulated resveratrol powder Reverse-Phase HPLC, Company—Waters, Detector: UV detector, Column—C18 Mobile phase—70(methanol):30(water), Flow rate—0.8ml/minute For the detection of resveratrol, the optimal wavelength of 306 nm was used A Resveratrol concentration was determined by measuring the peak areas and comparing them with the peak areas of known standards Sample preparation was carried out as per Kim et al., (2003) with slight modifications Microbiological studies Lactic acid bacteria, yeast and mold count and coliform count were recorded as per procedure by Wehr and Frank (2004) using the media MRS and M17 for Lactic acid bacteria, Potato dextrose agar for yeast and mold and MacConkey for coliform Results and Discussion Effect of encapsulated resveratrol powder on sensory parameters of yoghurt Preliminary trials were conducted with broader ranges of different levels of milk protein based Whey protein isolate (WPI) encapsulated resveratrol powder in yoghurt Three levels of fortificant encapsulated resveratrol powder (0, 1, and 3%), were used during the development of product Based upon sensory evaluation 1% levels of WPI based encapsulated resveratrol powder was selected considering its role as an enhancer of functionality More than above levels lead to bitter taste in the final product The values are shown in Figure 3104 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 The values for colour and appearance were 8.11 and 7.85 respectively for control and optimized yoghurt i.e WPI 1%.wall materials based encapsulated resveratrol powder In case of the body and texture, the scores obtained were 8.13 and for Control and WPI 1% The score for flavour of yoghurts were like 8.07 and 7.82 for control and WPI 1% The lower acceptability in terms of flavor may be associated with the release of slightly higher amount of encapsulated resveratrol during pasteurization or fermentation process When tried with selected level of incorporation of 1% WPI encapsulated powder, the entire sensory attribute like colour and appearance, body and texture, flavour and overall acceptability score shows no significant difference (p≤0.05) with control values Fermentation behavior during preparation of yoghurt with encapsulated resveratrol powder Titratable acidity in manipulating the physical properties of yoghurt The rheological properties of acid gels are affected by different starter concentration and incubation temperatures, which directly affect the rate of acidification pH During incubation period of yoghurt pH was taken after every one hour The values were expressed in Figure The initial pH of the milk used for yoghurt preparation was 6.64 At hrs control yoghurt had 6.52 pH But the yoghurt incorporated with encapsulated powder show lower pH at hrs, WPI 1% (6.504) The control sample set at 5:00 hrs with pH 4.21 and WPI 1% set at 4:30 hrs with 4.23 pH The slow fermentation is not desirable for yoghurt because of typical increases in syneresis and a breakdown of symbiotic relationship between starter bacteria (Tamime et al., 1989) Proximate composition of control and optimized yoghurt The acidity during the fermentation period was checked after every one hour The values were expressed in Figure The initial acidity of the milk before inoculation was 0.13% LA The acidity in both the samples after addition of culture increased immediately and ranged between 0.16 and 0.17 The use of high amount of inoculum (3% of milk taken), higher total solids and protein content resulted in immediate increase in the acidity of the samples The microbes got more protein due to incorporation of fortificant leads to increase in Titratable acidity At the end of h of incubation, the control yoghurt has shown the acidity of 0.828 % which was ideal acidity for the yoghurt to be shifted to cold store (about 5⁰ C) While WPI 1% has shown 0.82 % after 4: 30 hrs and set earlier than control The results findings are correlated with Lucey (2004) stated that an understanding of the gelation process during fermentation is critical The milk was standardized (3 % fat, 10% SNF) and yoghurt was prepared as per the standard procedure with slight modifications The incorporation of encapsulated resveratrol powder contains different components like oil, resveratrol and addition of protein based wall material (WPI) with addition of maltodextrin significantly (p≤0.05) affected the proximate composition of the samples The compositions varied as follows, fat (3.00 to 3.56) protein (3.95 to 4.2) carbohydrates, (5.25 to 5.62) ash (0.80 to 1.05) In addition to the lactose from milk, carbohydrates from encapsulated components (Maltodextrin) have contributed for the total carbohydrates in the experimental samples Control yoghurt contains 0.80% minerals and experimental samples showed slightly higher minerals content, which could have been contributed by added encapsulated resveratrol components and proteins 3105 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 Fig.1 Effect of encapsulated resveratrol powder on sensory parameters of yoghurt Average value n=6 Mean with different superscript differs significantly (p≤0.05) and all the values are expressed as (mean±SE) Fig.2 Fermentation behavior (Changes in Titratable Acidity) during preparation of yoghurt with encapsulated resveratrol powder Average value n=6 Fig.3 Fermentation behavior (Changes in pH) during preparation of yoghurt with encapsulated resveratrol powder Average value n=6 3106 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 Table.1 Proximate composition of control and optimized yoghurt Parameter Fat Protein Carbohydrates Minerals Total solids Calorific value Acidity (% LA) pH Syneresis (ml/100g) Antioxidant Activity Resveratrol content (mg/100g) Control 3.00±0.05ᵅ 3.95±0.00ᵅ 5.25±0.01ᵅ 0.80±0.01ᵅ 13.00±0.03ᵅ 63.8±0.01ᵅ 0.85±0.00a 4.32±0.00b 2.61±0.01b 53.34±0.01ᵅ NIL WPI 1% 3.56±0.01b 4.2±0.00ᵇ 5.62±0.01b 1.05±0.01b 14.41±0.00b 71.32±0.01b 0.86±0.00ᵇ 4.3±0.00a 2.31±0.01a 55.67±0.01b 34.102± 0.00ᵅ Average value n=6 Mean with different superscript differs significantly (p≤0.05) and all the values are expressed as (mean±SE) Table.2 Texture, colour profile and microbiological parameters of control and optimized Yoghurt Parameter Control Texture Profile parameters of Yoghurt 190.19±0.02ᵅ Firmness(g) 3974.49±0.01ᵅ Consistency (g.sec) -55.04±0.01ᵅ Cohesiveness(g) -112.53±0.01ᵅ Index of Viscosity (g.sec) Colour Profile parameters of Yoghurt 90.16±0.03ᵇ L -1.73±0.02ᵇ A 9.88±0.01ᵃ B Microbiological parameters of Yoghurt 6.6±0.00a L bulgaricus (log cfu/g) 6.88±0.00ᵃ S thermophilus (log cfu/g) NIL Coliforms(cfu/g) NIL Yeast and Mold(cfu/g) WPI 1% 234.27±0.01b 4865±0.01b -81.06±0.2b -121.17±0.01b 87.76±0.02a -1.17±0.02a 11.46±0.03ᵇ 6.84±0.00b 6.94±0.00b NIL NIL Average value n=6 Mean with different superscript differs significantly (p≤0.05) and all the values are expressed as (mean±SE) The results were correlated with the findings of Sivakumar et al., (2016) The proximate composition values are expressed in Table The fresh control yoghurt showed the acidity value of 0.85% LA, while the corresponding value for experimental sample varied between 0.86% LA Similarly the fresh control yoghurt showed the pH value of 4.32, while the corresponding value for experimental sample was 4.3.The fresh control yoghurt has showed the syneresis of 2.61 ml per 100 g of the sample, while the corresponding value for WPI 1% was 2.31 ml per 100 gram of the sample 3107 Int.J.Curr.Microbiol.App.Sci (2018) 7(8): 3102-3109 The antioxidant activity of control and optimized yoghurt values were varied in the range from 53.34 to 55.67%.The antioxidant activity of optimized yoghurt values were high due to incorporation of different milk protein based wall materials and resveratrol component Our results were correlated with the findings of Korhonen and Pihlanto (2006) stated that milk proteins, the most important source of bioactive peptides and an increasing number of bioactive peptides have been identified in milk protein hydrolysates and fermented dairy products The resveratrol content of control was nil while WPI 1% show 34.102 mg/100g of product This was due to incorporation of encapsulated resveratrol component Texture, colour profile and microbiological parameters of control and optimized Yoghurt Texture, colour profile and microbiological parameters of control and optimized Yoghurt values are expressed in Table The firmness of control and optimized yoghurt values were varied in the range from 190.19 to 234.27 (g) Results indicated that firmness was the lowest in control and highest in the samples fortified with WPI based encapsulated resveratrol powder The texture values firmness, consistency, cohesiveness and index of viscosity differed significantly (p≤0.05) between control and optimized yoghurt The texture values were interlinked between control and optimized yoghurt The incorporation of encapsulated resveratrol powder decreased (P≤ 0.05) the value of L* of the milk, therefore, it presented a darkening effect, probably due to the absorption of water by the fortificant, as L* value of foods is associated to the amount of free water in the surface of a product more than the complete product When fortificant was incorporated in yogurts, a*values towards less greenness and b* values more yellowness and a decrease in L* values less whiteness were observed Overall, colour profile parameters L, a, b differed significantly (P≤ 0.05) between the control and optimized yoghurt The control and optimized yoghurt the L bulgaricus count varied in the range of 6.6 to 6.84 (log cfu/g) and S thermophilus varied in the range of 6.88 to 6.94(log cfu/g) The optimized yoghurts were having more viable beneficial bacteria due to protein components present in the fortified substances provide the source of nutrient The coliform and yeast and mould counts were nil indicates may be the control and optimized products were prepared in good hygiene practices All the values were within the prescribed limits of FSSAI (2011) The sensory scores of optimized yoghurt (1% WPI protein based encapsulated powder) shows no 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during 16-19 Nov 2011 Sivakumar, S., Balasubramanyam, B.V., Rao, K.J., Dhas, P.H.A., and Surendra Nath, B 2016 Effect of Flaxseed oil and Flour on Sensory, Physicochemical and Fatty acid profile of the Fruit Yoghurt Journal of Food Science and Technology, 54(2): 368-378 Tamime, A.Y., Kalab, M., and Davies, G 1989 Rheology and Microstructure of strained yoghurt (labneh) made from cow‗s milk by three different methods Food Microstructure, 8: 125 – 135 Wehr, H.M., and Frank, J.F 2004 Standard Methods for the Examination of Dairy Products 17th ed Am Public Health Assoc., New York USA Harshita Sonarthi, S Sivakumar, Rekha Chawla, N Veena, S.K Mishra, Lovepreet Singh and Singh, P.K 2018 Quality Characteristics of Functional Yoghurt with Fortification of Encapsulated Resveratrol Powder Int.J.Curr.Microbiol.App.Sci 7(08): 3102-3109 doi: https://doi.org/10.20546/ijcmas.2018.708.331 3109 ... Veena, S.K Mishra, Lovepreet Singh and Singh, P.K 2018 Quality Characteristics of Functional Yoghurt with Fortification of Encapsulated Resveratrol Powder Int.J.Curr.Microbiol.App.Sci 7(08): 3102-3109... preparation of yoghurt with encapsulated resveratrol powder Average value n=6 Fig.3 Fermentation behavior (Changes in pH) during preparation of yoghurt with encapsulated resveratrol powder Average value... terms of CIE-LAB system (Hunter 1975) Antioxidant activity of yoghurt Radical scavenging activity of the yoghurt incorporated with encapsulated resveratrol Resveratrol content in fortified yoghurt